This invention pertains generally to scroll apparatus of the type wherein both scroll members rotate on parallel offset axes. More specifically, this invention relates to high-side co-rotating refrigerant scroll compressors wherein (a) compressed refrigerant gas and the oil entrained therein is discharged through the drive shaft of the drive scroll member into the discharge pressure portion of the compressor shell and wherein (b) the lubricant entrained in such discharge gas is disentrained in the discharge pressure portion of the shell and is directed to a sump therein.
With still more particularity, the present invention relates to the cooling of lubricating oil sourced from a sump in the discharge pressure portion of a hermetic high-side co-rotating refrigerant scroll compressor, prior to its use for bearing lubrication purposes, and to the diversion of such lubricant, after it has been used for lubrication purposes, away from the suction pressure portion of the compressor shell. As a result, cooling of the lubricating oil is achieved while the heating of suction gas prior to its entry into the compressor's compression mechanism is reduced, all to the benefit of the overall efficiency and reliability of the compressor.
Scroll compression apparatus is typically comprised of two scroll members, each member having an involute or spiroidal wrap. The wraps of the scroll members extend from an end plate and are in an interleaved relationship. Relative orbital motion of one scroll member with respect to the other causes the creation of a series of pockets between the scroll wraps which, in operation and dependent on the direction of scroll member rotation, decrease in volume so as to compress any gas trapped therein.
Scroll compressors are typically of a first type, in which one of the scroll members is fixed while the other orbits thereabout, or a second type, known as co-rotating scroll compressors, in which both scroll members rotate on parallel offset axes. In a co-rotating scroll compressor, one of the scroll members is characterized as the drive scroll member while the other is characterized as the idler scroll member. The drive scroll member is drivingly coupled to the idler scroll member and is itself driven by a drive shaft which extends from the drive scroll member end plate. The drive scroll member drive shaft penetrates and is coupled for rotation with the rotor of the motor by which the compressor is driven.
Hermetic compressors (compressors in which both the drive motor and compression mechanism are disposed in a hermetic shell), including those of the scroll type, can be categorized as being of the high or low side type. A high side compressor is one in which the drive motor is disposed in a portion of the compressor shell in which discharge gas is found and which is at compressor discharge pressure when the compressor is in operation. A low side compressor is one in which the drive motor is disposed in the portion of the compressor shell in which suction gas is found and which is at suction pressure when the compressor is in operation.
It has prospectively been determined, with respect to hermetic co-rotating scroll compressors, to be advantageous to employ a high side design and to use the drive shaft of the drive scroll member to communicate compressed refrigerant gas out of the compressor's compression mechanism into the discharge pressure portion of the compressor shell. Exemplary in that regard are U.S. Pat. Nos. 4,927,339 and 5,080,566, the former being assigned to the assignee of the present invention and being incorporated herein by reference.
It has also prospectively been determined to be advantageous in such a compressor to use the pressure that exists in the discharge pressure portion of the shell of the compressor (when the compressor is in operation) to drive oil from an oil sump in the discharge pressure portion of the shell to the bearings in which the scroll members are rotatably supported. It is, of course, known to be advantageous to cool oil used for bearing lubrication purposes prior to the use of such oil in the lubrication process. It is likewise known to be advantageous, with respect to compressor efficiency and reliability, to minimize the heating of compressor suction gas prior to entry of that gas into a compressor's compression mechanism.
These advantages are difficult to achieve in hermetic compressors, particularly (1.) where the source of bearing lubricant is a sump in the relatively hot discharge pressure portion of the compressor's hermetic shell, (2.) where the compressor's compression mechanism is in the suction pressure portion of its shell and (3.) where one of the bearings being lubricated comprises a boundary between the discharge pressure portion and suction pressure portion of the compressor. There continues to be a need for a viable arrangement in a hermetic high-side co-rotating scroll compressor by which to cool the oil used to lubricate such bearings and by which to prevent or minimize the entry of such bearing lubricant, subsequent to its having been heated in the bearing lubrication process, into the suction pressure portion of the compressor shell.